These machines feature an extremely rigid structure, with a single column fixed to the floor. The structure is highly functional for machining large diameters, offering considerable capacity to increase the workable diameter, leaving three sides completely open for easy workpiece loading. The frame consists of a base containing the spindle and the mechanical gearbox or direct drive for the rotation of the platform, and a single column with guides for the moving of the movable crossrail. The crossrail is designed with a shape and size that are more than adequate to withstand the most severe working conditions, with a section designed using finite element analysis and optimized for the X-axis travel. A sophisticated mechanical compensation mechanism for the crossrail and the column has been developed over years of experience. Three different types of tie rods act to minimize the geometric deflections generated by the large masses moving on the machine’s linear axes, ensuring the lathe’s geometric stability.